The collective wobbling motion is a specific signature for the identification of the rare triaxially deformed shape of nuclei, which is characterized by different lengths along each of the three principal axes. It has already been established in the mass regions A~160 and A~130. Most of the observed collective wobbling modes are found in odd-proton nuclei and can be interpreted as a transverse wobbling motion with the wobbling frequency decreasing with the spin I. In this colloquium, four newly observed wobbling modes will be introduced: (1) the transverse wobbling motion in the odd-neutron nucleus 105Pd; (2) the transverse wobbling motion in the even-even nucleus 130Ba; (3) the longitudinal wobbling motion in the nucleus 187Au, whose wobbling frequency increases with spin; and (4) the coexistence of two different types of wobbling modes in 183Au. Their specific features regarding the wobbling frequency, the mixing ratio of transitions, the electromagnetic transition probabilities, as well as the angular momentum geometry will be discussed. These features are then studied in a theoretical framework based on covariant density functional theory and the triaxial particle-rotor model.
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Meeting ID: 984 5733 2925
Peter Thirolf (LMU), Norbert Kaiser (TUM)